Lead-Free Double Perovskite Cs₂AgIn_1-x Er _x Cl₆ Fluoride Glass with Highly Stable Mid-Infrared Luminescence for Monitoring CO₂ in Hydrogen Energy

Carbon dioxide makes the hydrogen combustion processunstable anddestructive, thus affecting the efficiency and effectiveness of hydrogenenergy use. Thus, it is very important to monitor CO2 inhydrogen gas. All-inorganic perovskites are used for optical sensingdue to their excellent optical properties, and photoluminescence sensorsmade from them can monitor gas concentration. However, the toxicityand intrinsic instability of lead-based perovskites have limited theircommercial development. Meanwhile, perovskites have rarely been studiedin the mid-infrared range. Herein, Cs2AgIn1-x Er x Cl6-ZBLANperovskite fluoride glasses with outstanding mid-infrared luminescenceare successfully prepared. A CO2 monitor device is fabricatedusing a Cs2AgIn1-x Er x Cl6-ZBLAN perovskite fluorideglass. The dense and inert nature of the glass is used to isolatethe lead-free perovskite Cs2AgInCl6 from theexternal environment, thereby improving stability. The luminescenceintensity of the Cs2AgIn1-x Er x Cl6-ZBLAN perovskitefluoride glass can still be maintained at more than 90% of its originallevel after 35 h of continuous UV lamp irradiation at 365 nm. Thesubstitution of Er3+ for In3+ to form Cs2AgIn1-x Er x Cl6-ZBLAN perovskite fluoride glasses makes thempromising candidates for future mid-infrared-emitting materials. The concentration of CO2 gasin H-2 gas can be monitored with a device made of a Cs2AgIn1-x Er x Cl6-ZBLAN perovskite fluoride glass. Green, lead-freematerialsare conducive to the sustainable development of ecology.